Delivering adenosine and antioxidants together could serve as an improved approach for the treatment of acute inflammation.

Cyclosporin A (CsA) is a molecule with well-known immunosuppressive properties. As it also acts on the opening of mitochondrial permeability transition pore (mPTP), CsA has been evaluated for ischemic heart diseases (IHD). However, its distribution throughout the body and its physicochemical characteristics strongly limit the use of CsA for intravenous administration. In this context, nanoparticles (NPs) have emerged as an opportunity to circumvent the above-mentioned limitations. We have developed in our laboratory an innovative nanoformulation based on the covalent bond between squalene (Sq) and cyclosporin A to avoid burst release phenomena and increase drug loading. After a thorough characterization of the bioconjugate, we proceeded with a nanoprecipitation in aqueous medium in order to obtain SqCsA NPs of well-defined size. The SqCsA NPs were further characterized using dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryoTEM), and high-performance liquid chromatography (HPLC), and their cytotoxicity was evaluated. As the goal is to employ them for IHD, we evaluated the cardioprotective capacity on two cardiac cell lines. A strong cardioprotective effect was observed on cardiomyoblasts subjected to experimental hypoxia/reoxygenation. Further research is needed in order to understand the mechanisms of action of SqCsA NPs in cells. This new formulation of CsA could pave the way for possible medical application.

For several decades, various peptides have been under investigation to prevent ischemia/reperfusion (I/R) injury, including cyclosporin A (CsA) and Elamipretide. Therapeutic peptides are currently gaining momentum as they have many advantages over small molecules, such as better selectivity and lower toxicity. However, their rapid degradation in the bloodstream is a major drawback that limits their clinical use, due to their low concentration at the site of action. To overcome these limitations, we have developed new bioconjugates of Elamipretide by covalent coupling with polyisoprenoid lipids, such as squalenic acid or solanesol, embedding self-assembling ability. The resulting bioconjugates were co-nanoprecipitated with CsA squalene bioconjugate to form Elamipretide decorated nanoparticles (NPs). The subsequent composite NPs were characterized with respect to mean diameter, zeta potential, and surface composition by Dynamic Light Scattering (DLS), Cryogenic Transmission Electron Microscopy (CryoTEM) and X-ray Photoelectron Spectrometry (XPS). Further, these multidrug NPs were found to have less than 20% cytotoxicity on two cardiac cell lines even at high concentrations, while maintaining an antioxidant capacity. These multidrug NPs could be considered for further investigations as an approach to target two important pathways involved in the development of cardiac I/R lesions.

Développement de nouvelles nanoformulations pour la thérapie cardiaque: L'ischémie/reperfusion est une maladie multifactorielle impliquant de multiples voies de signalisation. Les traitements actuels des lésions de reperfusion n'offrant que des avantages très limités, il est devenu nécessaire d'utiliser des stratégies impliquant plusieurs molécules agissant sur différentes voies ou facteurs. L'utilisation de la nanomédecine pour protéger le principe actif d'une dégradation prématurée et pour améliorer le ciblage du médicament souffre généralement de limitations telles qu'un taux de charge très faible.Les nanoparticules à base de squalène développées dans notre laboratoire présentent l'avantage de permettre une plus grande teneur en médicament et de limiter sa libération prématurée, tout en permettant l'encapsulation de plusieurs principes actifs.L'objectif principal de cette thèse était d'appliquer la méthode de squalénisation pour développer des nanoformulations de nouveaux bioconjugués de peptides thérapeutiques actifs dans l'ischémie/ reperfusion cardiaque. Nous avons tout d'abord conjugué chimiquement le squalène à la cyclosporine A ainsi qu'à l'élamipretide. Puis des nanoparticules monodrogues (cyclosporine A seule) et multidrogues (cyclosporine A et élamipretide ont été obtenues à partir de ces bioconjugués et caractérisées par cryomicroscopie, diffusion des rayons X et des neutrons. Pour finir, nous avons étudié, sur deux lignées cellulaires cardiaques, la cytotoxicité, internalisation et l'effet protecteur en hypoxie/reoxygenation des nanoparticules multidrogues et/ou monodrogues.